By-pass damper device



Dec. 26, 1967 B. M. SOPHER ETAL BY-PASS DAMPER DEVICE Filed Dec. 9, 1963 F/a TUFE/A/f INVENTORS.

United States Patent 3,360,005 BY-PASS DAMPER DEVICE Bruce M. Sopher and Joseph W. Collins, Torrance, Califi,

assignors to Farr Company, El Segundo, Calif., a corporation of California Filed Dec. 9, 1963, Ser. No. 329,099 3 Claims. (Cl. 137-5121) This invention relates to a normally closed device which opens under predetermined conditions and in particular is directed to an arrangement in an air-using system wherein the normal air supply through certain apparatus may be unintentionally interrupted or terminated and the device of this invention will admit air to the system to supplant the interrupted or terminated air supply.

There are numerous air systems which handle or use a large quantity of air and develop relatively low pressures at the intakes to the systems such as the intakes to gas turbines and large internal combustion engines. These air systems are usually provided with air filtering or cleaning devices at the intakes for removing undesirable particles, moisture or the like from the air being drawn into the particular system as protection for that system. It has been observed that in certain situations the intakes to these air systems may become blocked or at least partially closed such as by an accumulation of frost, snow, leaves and the like in the air filtering or cleaning apparatus provided in the intake to the system. When this blocking or partial closing occurs rapidly or continues un-noticed these systems which use large quantities of air will produce a relatively high suction, i.e., extremely low pressure in the intake area. It has been found that this can cause intake ducting to collapse or components and parts of the intake ducting and air filtering apparatus to become dislodged or broken and then drawn into the air-using system. As a result, extensive damage may be cause to an air system such as turbine, internal combustion engine, or the like.

This problem of damage being caused by clogging of the intake apparatus, such as an air filter, that is intended to prevent damage to the air system has been recognized and as a result devices have been provided for producing an alternate air intake during these adverse situations. In general the present conventional devices are positioned in the intake ducting downstream from the air cleaning or filtering device and are provided with a plurality of louvers, doors or the like for opening upon occurrence of an unusually low intake pressure caused by one of such aforementioned adverse situations. It is only desirable that these louvers open upon occurrence of such adverse situations where the normal air intake path is blocked or abnormally restricted and therefore the louvers of heretofore conventional devices have been spring biased or weighted for continuously being urged toward the closed position. However since these louvers are continually urged in the closed direction an increasing pressure dilferential will be required to increase the amount of opening of the louvers and yet as the louvers are opened some air will be admitted to thereby reduce the pressure differential and tend to permit the louvers to close. Further it has been found necessary and extremely difiicult with these conventional devices to achieve an appropriate compromise whereby the louvers are urged closed by the proper force to result in opening upon the occurrence of a predetermined abnormally low pressure indicating clogging of the normal intake and are urged closed by a sufiicient force for the louvers to accomplish an air-tight closure and prevent vibration noises and rattling.

Accordingly, it is an object of this invention to provide a device for use in association with the intake of an air using system for providing an alternate air inlet upon demand for additional air by the air system wherein the closure means are movable between opened and closed positions, are maintained in the closed position by a predetermined high force and yet are ma ntained in the opened position by a very low continuing force.

Another object of this invention is to provide an air intake by-pass damper device for use with systems using large quantities of air wherein movable dampers are maintained in the closed position predominantly by the force of magnets engaging the dampers only in the closed position whereby a relatively small force is needed to maintain the dampers in an open position compared to the force required to open the dampers.

A further object is to provide a by-pass damper device for intakes of air systems wherein magnetic means maintain pivotally mounted dampers in the closed position and are adjustable in number and in their distance from the pivotal axis of the dampers for permitting free selection of the desired force resistive to opening of the dampers.

Other and more detailed objects and advantages of this invention will appear from the following description and the accompanying drawing wherein:

FIGURE 1 is a schematic illustration of a typical installation employing the device of this invention.

FIGURE 2 is a fragmentary elevation view of .a portion of the device of this invention as viewed from the inside of the intake to the air system.

FIGURE 3 is a fragmentary sectional elevational view of the device of this invention taken substantially on the line 33 as shown in FIGURE 2.

FIGURE 4 is an enlarged sectional elevation similar to FIGURE 3 and further illustrating certain of the details of the device of this invention.

FIGURE 5 is a sectional elevation view similar to FIGURE 4 illustrating a modified form of the device of this invention.

Referring now in further detail to FIGURE 1, the bypass damper device, generally designated 10, of this invention is illustrated as being installed in the sidewall 11 of an intake duct 12 of an air using system 13, such as the turbine illustrated. Upstream from the location of the device 10 in the intake duct 12 the normal inlet 14 to the system is provided with an air filter 15 or any other type device which normally creates some restriction to air flow into the duct 12 and may create extremely high resistance to air flow upon the occurrence of abnormal conditions such as excessive accumulation of frost,

snow, leaves, debris, etc. The exact location of device 10 relative to the turbine and air filter is not critical so long as device 10 will serve as an alternate air inlet to inlet 14 for the turbine or air system 13.

The device 10 includes a frame 20 which forms a housing for mounting in an opening provided in the sidewall 11 of the intake duct 12. The frame 20' is appropriately secured to the intake duct 12 by any convenient means (not shown) and cooperates with the opening provided whereby any air passing through the opening in the intake duct 12 must pass within the confines of the frame 20. A plurality of sub-frames 21, such as the four shown, are mounted within the frame 20. Each sub-frame 21 forms a rigid rectangular member having sides 22 and inwardly extending flanges 23 forming an opening 24. The sub-frames 21 are secured to the frame 20 and to each other by any convenient means such as weld 25 to occupy the entire opening through frame 20. While four sub-frames 21 have been shown as being positioned vertically one above the other and described. as having a particular structure it is to be understood and will readily appear to those skilled in the art that more or fewer may be used and that other structural arrangements may be employed without departing from this invention.

A louver, door or damper 26 is pivotally mounted in each sub-frame 21 by any convenient means such as a hinge 27 having one portion connected to the sub-frame and the other portion connected to the damper. The damper 26 is of a suflicient size and properly positioned for completely closing the opening 24 when the damper is in the closed position illustrated in FIGURE 4 and by solid lines in FIGURE 3. With respect to the direction of air flow the damper 26 is mounted downstream (or inside) of the flanges 23 forming the opening 24 whereby pivoting of the dampers 26 about the hinge 27 is accomplished by pivoting the dampers inwardly in the direction of air flow as illustrated by the phantom lines in FIGURE 3. While it is not essential to this invention it is preferred that the frame be mounted in a sidewall or the bottom of the intake duct 12 with the hinges 27 along the upper edge of the attached dampers 26 whereby the force of gravity will tend to return the dampers to the closed position. It will be readily appreciated that the frame 20 may be mounted in other positions and any convenient counter-balancing means or light spring biasing means may be provided for urging the dampers 26 to the closed position during normal conditions of intake air pressure differential.

A plurality of vertically extending supports 28 are mounted in and across the front of frame 20 in spaced relation. Each support 28 is provided with a plurality of vertically spaced holes 29 opposite each damper 26. A plurality of magnetic latch assemblies, generally designated 30, are provided and at least one magnetic latch assembly 30 is mounted in a hole 29 opposite each damper 26 for engaging that damper in the closed position. The magnetic latch assembly 30 may be constructed in any convenient way such as by securing a bolt 31 to a conventional cup-shaped magnet 32 with the bolt passing through a hole 33 in the magnet and a lock nut 34 clamping the magnet to the bolt. The bolt is passed through a hole 29 and a pair of nuts 35 and 36 are locked together on the bolt for attaching the magnetic latch assembly 30 to the support 28. The nuts 35 and 36 and lock nut 34 are spaced a greater distance than the thickness of support 28 thereby only loosely connecting the magnetic latch assembly 30- to the support. Further, a resilient rubber ring 37 is positioned between the head of bolt 31 and the magnet 32 to produce a flexible connection between the bolt and magnet. In this manner the entire magnetic latch assembly 30 as well as the magnet 32 itself may adjust to the appropriate position for accomplishing surface contact between the damper 26 and the magnet for producing the maximum magnetic retentive force between the magnet and the damper. The dampers 26 are preferably of an iron base metal susceptible to magnetic attraction or a piece of such metal is provided on each damper 26 adjacent each support 28.

With the damper 26 engaging the magnet 32- of the magnetic latch assembly 30, the damper 26 is maintained in the closed position by this magnetic force which completely predominates any force of gravity or spring biasing which tends to urge the damper toward the closed position. When the pressure within the intake duct 12 reaches an abnormally low level such as by reason of extreme clogging of filter 15 the atmospheric pressure will urge the dampers 26 inwardly to their open positions and the continued flow of air through the dampers will maintain them in their open positions. Upon unclogging of filter 15 by maintenance or through melting of the frost or snow, the normal air flow through inlet 14 will resume thereby reducing the quantity of air flow through the device 10 and permitting the dampers 26 to automatically return to their closed positions. The dampers 26 will return to their closed positions provided the gravitational or spring biasing forces acting on the dampers are sufficient to overcome this reduced air flow through the openings 24 of the device 10. Upon returning to the closed positions the dampers 26 will again be engaged by the 5 magnets 32 for retaining the dampers in this position until re-occurrence of clogging of the inlet 14.

As described, the supports 28 are provided with a plurality of vertically spaced holes 29 adjacent each damper 26 and these holes permit installation of the magnetic latch assembly 30 in any desired vertical location relative to the hinge 27 of the damper 26. In this manner the moment of resistive force retaining the damper 26 in the closed position may be adjusted by adjusting the distance from the pivotal axis even though the magnets 32 are of the permanent type and their forces produced cannot be varied for the given magnet. Moreover, since there are a plurality of supports 28 and therefore there may be a plurality of magnetic latch assemblies 30 engaging each damper, it is possible to vary this number of magnetic latch assemblies 30 engaging each damper 26 for producing the desired retentive force. This combination of flexibility of number of magnetic latch assemblies 30 and location of each assembly relative to the pivot hinge 27 produces a versatility of adjustment previously unknown and allows accurate preselection of the desired intake pressure level needed for opening the dampers 26.

Referring now to FIGURE 5, some modifications in details of construction of the device of this invention are illustrated. The sub-frames 21a and supports 28a may be substantially the same as sub-frames 21 and supports 28 heretofore described and may be mounted in a frame similar to described frame 20. Dampers 26a are similar to dampers 26 and each is mounted by a hinge 27a to the associated sub-frame 21a. A gasket 40 may be provided between the flange 23a of the sub-frame 21a and the damper 26a and located for surrounding the opening 24a in the sub-frame. The gasket 40 may be secured to either the damper 26a or theflange 23a of the sub-frame 21a. In this manner a completely air tight seal and a more quiet operation may be achieved. It will readily appear to those skilled in the art that a gasket 40 could also be provided with the embodiment illustrated in FIGURES 14. A permanent magnet 32a is secured to damper 26a adjacent a support 28a by any convenient means such as a bolt 41 passing through the magnet 32a and the damper 26a with a pair of nuts 42 and 43 looking the magnet in position. Welding 44 may be used for securing nut 43 to the damper 26a to prevent inadvertent releasing of the described nuts, bolt and magnet. A striker plate 45 has a threaded shank 46 for extending through a hole 29a in the support 28a and a pair of nuts 47 and 48 engage shank 46 for loosely locking the striker plate 45 to the support 28a. The striker plate 45 is of an iron base metal for being attracted by the magnet 32a. In the closed position of damper 26:: the magnet 32a makes surface contact with the striker plate 45 for producing the magnetic force to retain the damper in this closed position. By this arrangement the magnetic latch assembly 30 of the previously described embodiment is replaced by this cooperating magnet 32a and striker plate 45 assembly.

Having fully described our invention it is to be understood that we do not wish to be limited to the specific details herein set forth or to the details of construction illustrated in the drawings, but rather our invention is of the full scope of the appended claims.

We claim:

1. In an air by-pass arrangement for use in an opening in an air supply system, the combination of:

' closure means pivotally mounted relative to said opening for positioning to close the opening,

said closure means being pivotable inwardly relative to the opening to an open position for admitting air through the opening,

a bracket means positioned substantially parallel to said closure means in the closed position of the clo sure means and extending at a substantial angle to the pivotal axis of the closure means, and magnetic means loosely mounted on said bracket means for engaging said closure means in the closed position of said closure means, and said magnetic means being releasably mounted and movable to various locations along said bracket means for positioning at pre selected distances from the pivotal axis of the closure means to produce preselected forces resisting the said movement from the closed position to said open position.

2. In an air by-pass arrangement for use with an auxiliary opening in the intake of an air system normally drawing air from the atmosphere through restrictive means in another opening, the combination of:

a frame for cooperating with said auxiliary opening,

a plurality of dampers pivotally mounted in said frame across said auxiliary opening said dampers cooperating with each other and with said frame for completely closing said auxiliary opening,

said dampers pivotable from said closed position to open positions for admitting air from the atmosphere to the air system,

and a plurality of individual magnetic means loosely mounted in said frame and positioned in laterally spaced relation to each other in association with each said damper for engaging that associated in surface contact relationship damper in the closed position,

each said magnetic means releasably mounted for se lectively positioning at varying locations radially spaced from the pivotal mounting of that associated damper for magnetically exerting a predetermined resistive force dependent on said radial spacing to be overcome by the air demand of the air system upon abnormal increase in the air flow restriction by the restrictive means for opening said dampers and admitting the air to the air system.

3. In an air by-pass arrangement for use with an auxiliary opening in the intake of an air system normally drawing air from the atmosphere through restrictive means in another opening the combination of:

a frame for cooperating with said auxiliary opening,

a plurality of dampers pivotally mounted in said frame across said auxiliary opening, said dampers cooperating with each other and with said frame for completely closing said auxiliary opening,

compressible gasket means mounted between said frame and dampers for sealing therebetween,

said dampers pivotable from said closed position to open positions for admitting air from the atmosphere to the air system,

a plurality of individual magnetic means loosely mounted in said frame and positioned in laterally spaced relation to each other in association with each said damper for engaging that associated damper in surface contact relationship in the closed position and compressing said gasket means,

each said magnetic means radially spaced from the pivotal mounting of that associated damper for magnetically resisting the opening of that damper,

and means for adjusting said radial spacing of each individual magnetic means for exerting a predetermined resistive force to be overcome by the air demand of the air system upon abnormal increase in the air flow restriction by the restrictive means for opening said dampers and admitting air to the air system.

References Cited UNITED STATES PATENTS 2,161,471 9/1939 Hueglin 98--110 2,496,691 2/1950 Berry. 2,739,521 3/ 1956 Spear.

FOREIGN PATENTS 489,763 1954 Italy.

WILLIAM F. ODEA, Primary Examiner.

H. M. COHN, Assistant Examiner. 

1. IN AN AIR BY-PASS ARRANGEMENT FOR USE IN AND OPENING IN AN AIR SUPPLY SYSTEM, THE COMBINATION OF: CLOSURE MEANS PIVOTALLY MOUNTED RELATIVE TO SAID OPENING FOR POSITIONING TO CLOSE THE OPENING, SAID CLOSURE MEANS BEING PIVOTABLE INWARDLY RELATIVE TO THE OPENING TO AN OPEN POSITION FOR ADMITTING AIR THROUGH THE OPENING, A BRACKET MEANS POSITIONED SUBSTANTIALLY PARALLEL TO SAID CLOSURE MEANS IN THE CLOSED POSITION OF THE CLOSURE MEANS AND EXTENDING AT A SUBSTANTIALLY ANGLE TO THE PIVOTAL AXIS OF THE CLOSURE MEANS, AND MAGNETIC MEANS LOOSELY MOUNTED ON SAID BRACKET MEANS FOR 